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The Active Region Evolution and Activity of Halloween 2003

The Active Region Evolution and Activity of Halloween 2003. Peter T. Gallagher (L-3 Com GSI) and R. T. James McAteer (NRC) at NASA Goddard Space Flight Center. 18 Oct - 4 Nov, 2003 Activity Overview. X17.2. In 17 days there were: 3 of the largest regions of cycle 23.

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The Active Region Evolution and Activity of Halloween 2003

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  1. The Active Region Evolution and Activity of Halloween 2003 Peter T. Gallagher (L-3 Com GSI) and R. T. James McAteer (NRC) at NASA Goddard Space Flight Center Peter T Gallagher (NASA/GSFC)

  2. 18 Oct - 4 Nov, 2003 Activity Overview X17.2 • In 17 days there were: • 3 of the largest regions of cycle 23. • One of the largest regions in recorded history. • 3-ray line flares observed by RHESSI. • 12 X-class flares. • X28+, X17.2, and an X10. • 41 M-class flares. • 62 C-class flares. • At least 15 “halo” CMEs. • ~5 days of enhanced >100 MeV protons. X10.0 X8.3 Peter T Gallagher (NASA/GSFC)

  3. NOAA 10484: Summary • Dates observed: 18 - 29 Oct (11 days) • Maximum area: 1940 h at ~W01 (23 Oct) • Hale/Mount Wilson Class:  • McIntosh Class: Ekc • Maximum number of spots: 53 • Flare numbers: 30 C-class, 14 M-class, 2 X-class • Flare rates (flares/day): 2.73 (C-class), 1.27 (M-class), 0.18 (X-class) Peter T Gallagher (NASA/GSFC)

  4. NOAA 10486: Summary • Dates observed: 23 Oct - 4 Nov (12 days) • Maximum area: 2680 h at ~W25 (30 Oct) • Hale/Mount Wilson Class:  • McIntosh Class: Fkc • Maximum number of spots: 94 • Flare numbers: 15 C-class, 20 M-class, 8 X-class and 3 -ray • Flare rates (flares/day): 1.25 (C-class), 1.66 (M-class), 0.66 (X-class) Peter T Gallagher (NASA/GSFC)

  5. NOAA 10488: Summary • Dates observed: 26 Oct - 4 Nov (9 days) • Maximum area: 1830 h at ~W30 (30 Oct) • Hale/Mount Wilson Class:  • McIntosh Class: Fkc • Maximum number of spots: 61 • Flare numbers: 17 C-class, 7 M-class, 2 X-class • Flare rates (flares/day): 1.88 (C-class), 0.77 (M-class), 0.22 (X-class) Peter T Gallagher (NASA/GSFC)

  6. The Active Regions of Oct-Nov 2003 Peter T Gallagher (NASA/GSFC)

  7. GOES X-rays Notable Events: • 18 Oct - 4 Nov • X17.2 (28 Oct) • X10.0 (29 Oct) • X8.3 (2 Nov) • X28+ (4 Nov) Peter T Gallagher (NASA/GSFC)

  8. GOES Protons • First >100 MeV increase from X1.2 on Oct 26 (NOAA 10484 at ~W38). • All >100 MeV increase from regions with E08 < Lon < W90. • 4 proton events from NOAA 10486 at: • E08 (X17.2 28 Oct) • W02 (X10.0 29 Oct) • W56 (X8.3 2 Nov) • W90 (X28 4 Nov). Peter T Gallagher (NASA/GSFC)

  9. The X-rated Details • From http://beauty.nascom.nasa.gov/~ptg/oct-nov-2003-xflares.html W70 < Lon < W90 E08 < Lon < W70 E90 < Lon < E08 Peter T Gallagher (NASA/GSFC)

  10. Sun-Earth Connectivity • Assume Parker spiral of form: • See a space weather report for Mars at http://beauty.nascom.nasa.gov/~ptg/mars Peter T Gallagher (NASA/GSFC)

  11. NOAA 10484 • X1.1 (19 Oct) / X1.2 (26 Oct) Peter T Gallagher (NASA/GSFC)

  12. NOAA 10486 • X17.2 (28 Oct) / X10.0 (29 Oct) / X8.3 (2 Nov) / X28 (4 Nov) • X17.2 (28 Oct) / X10.0 (29 Oct) / X8.3 (2 Nov) / X28 (4 Nov) Peter T Gallagher (NASA/GSFC)

  13. NOAA 10488 • X3.7 and X2.9 (3 Nov) Peter T Gallagher (NASA/GSFC)

  14. RHESSI Flare Locations: NOAA 0484 Peter T Gallagher (NASA/GSFC)

  15. RHEESI Flare Locations: NOAA 0486 Peter T Gallagher (NASA/GSFC)

  16. RHESSI Flare Locations: NOAA 0488 Peter T Gallagher (NASA/GSFC)

  17. Magnetic Flux Changes • NOAA 10484 • B+ decays slowly. • B- increases then decays. • NOAA 10486 • Growth in B+ until central meridian, then decay. • Growth in B- until central meridian, then remains constant. • B- shows rapid change during X17.2. • NOAA 10488 • Rapid growth in B+and B-over 2-days. Peter T Gallagher (NASA/GSFC)

  18. X17.2 Polarity Balance • NOAA 10484 • B-> B+ • B+~ const • dB-/dt > 0 • NOAA 10486 • B+ > B- then B+ < B- • dB-/dt > 0 • NOAA 10488 • B+ > B- • dB+/dt > dB-/dt Peter T Gallagher (NASA/GSFC)

  19. Horizontal Gradient • Converging photospheric flows sweep opposite polarity fields towards the neutral line of the  (bipolar groups do NOT form significant neutral lines, transverse gradients, and hence flares). • Large transverse gradients in the photospheric magnetic field are observed across the neutral line of large  spots (Patty & Hagyard, 1986; Zhang et al., 1994). • Over a period of hours, the continued concentration of opposite polarities in a relatively small area leads to strong transverse gradients (Gallagher, Moon, & Wang 2002). • energy_buldup (hrs - days) >> energy_resease (secs - mins) • An instability in the corona results in the release of stored (Priest & Forbes; Antiochos et al.) Peter T Gallagher (NASA/GSFC)

  20. NOAA 10484 • Automated neutral line and gradient measurements. • Large field gradients observed across multiple neutral lines. • X1.1 (19 Oct) • X1.2 (26 Oct) Peter T Gallagher (NASA/GSFC)

  21. NOAA 10486 • Strong transverse gradients in Blos. • Multiple long and complex neutral lines. • X17.2 (28 Oct) • X10.0 (29 Oct) • X8.3 (2 Nov) Peter T Gallagher (NASA/GSFC)

  22. NOAA 10488 • Short neutral lines. • Strong gradients. • X2.7 (3 Nov). • X3.9 (3 Nov). Peter T Gallagher (NASA/GSFC)

  23. NOAA 10486 NOAA 10484 NOAA 10488 Size Distribution of Sunspot Groups (1900-2000) • Maximum areas: • NOAA 10484 = 1940 h • NOAA 10486 = 2680 h • NOAA 10488 = 1830 h Peter T Gallagher (NASA/GSFC)

  24. Size Distribution of Sunspot Groups (1874-2003) • NOAA 10486: in largest 5% of regions • NOAA 10484 and 10488: in largest 24% of regions Peter T Gallagher (NASA/GSFC)

  25. X28! NOAA 0486 Area, Class and Activity • Sammis et al., ApJ, 540, 583, (2000) • 2789 active regions (1989-1997) • All flares above X4 come from 11  regions with areas >1000 h. X M C B Peter T Gallagher (NASA/GSFC)

  26. SOHO EIT 19.5 nm (18 Oct - 5 Nov) Peter T Gallagher (NASA/GSFC)

  27. Summary • All three regions were large (ie, >1500 h), multipolar (ie, magnetically complex), highly dynamic (ie, changing flux distribution), with strong gradients (ie, > 50 G/Mm) and long neutral lines (ie, >60 Mm): magnetic properties essential to flare and CME production. • NOAA 10486 was particularly unusual in terms of its size, complexity, and activity. One of the largest and most active regions in the past 100-years. • Does the formation of these region at such a late stage in the solar cycle provides evidence for nonlinear dynamo action? • Does the emergence of several regions imply the regions resulted from global rather than local effects? • Much work still to be done to understand the relationship between the field configuration in the photosphere with the activity observed in the corona. Peter T Gallagher (NASA/GSFC)

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